A study of congenital transmission with a non-virulent Toxoplasma gondii isolate obtained from sheep in the mouse model Leila Danehchin1 1, Gholamreza Razmi 2 © ℗ 1 Department of Pathobiology, Faculty of Veterinary Medicine , Ferdowsi university of Mashhad 2 Department of Pathobiology, Faculty of Veterinary Medicine , Ferdowsi university of Mashhad, Iran Background: Toxoplasmosis is an important zoonotic disease that can cause abortion in human and sheep. In the present study, the effect of T.gondii strain isolate that was obtained from sheep was examined to produce congenital infection in the mouse model by IFAT and PCR. Materials and Method: Twenty pregnant Swiss breed mice were divided four groups. The groups 1 to 3 were orally infected with 20 sporulated oocysts of T.gondii on day 5, 10 and 15 pregnancy, respectively. The group 4 was determined as control negative. The Fertility, litter size and mortality rate were monitored within two generations of consecutive pregnancies. Results: During a three months period of the study, all infected females showed antibodies against T.gondii, while the non- infected control mice remained seronegative. There was no difference in the fertility rate of the dams, or in the litter size of infected and control mice. Mortality of offspring of the first and second generations of the infected dams was observed within the first week of life. In this study , the rate of vertical transmission in group 1, 2 and 3 were 100% , 60% and %50 in first generation ,respectively . In second generation, 82% of offspring were infected with Discussion: Based on the results, it is concluded that a non-virulent T.gondii isolate from sheep could be congenitally transmitted through successive generation of mice

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